Designating the Urban Interstates
Design Standards 1944
Other proposed standards from Appendix V of Interregional Highways included:
Where elevation or depression was necessary to avoid intersections, "depression of the highway, if financially feasible, generally shall be preferred to elevation." Where the highway must be elevated, it shall be "by means of a structure of adequate and pleasing design."
Service streets were to be provided, designed as one-way streets not less than 24 feet wide, at each side of the Interregional System for the service of property.
Design speed "shall be as high as practicable, consistent with the topography, proximity of urban improvements, and expected traffic volume." With those limits, a design speed higher than 50 miles per hour "will usually be impracticable."
Sections that are expected to carry 20,000 vehicles or more a day should be designed for three lanes in each direction, each lane 12 feet wide. Opposing traffic should be separated by a raised median strip at least 4 feet wide. Sections designed for traffic volumes under 20,000 vehicles a day should have two lanes in each direction, 12 feet wide, with opposing traffic separated in the same way as on higher volume segments.
Shoulders should be 10 feet wide and contrasting in texture and preferably in color with the adjoining pavement. As an alternative, the outer lanes would have "mountable curbs, outside and flush with the top of which, there shall be provided, if financially feasible, an area not less than 10 feet wide, which shall be reserved for the temporary accommodation of disabled or other stationary vehicles."
Grades "shall preferably be not steeper than 3 percent and shall in no case exceed 5 percent."
Right-of-way should be acquired in its entirety "by outright purchase or condemnation" to accommodate "the construction of pavements, median strips, areas for deceleration, acceleration, and maneuvering, standing areas, side slopes, ramps, retaining walls, barrier strips, and service streets, or such of these facilities as may be required at any point."
Overpasses should allow a minimum clearance of 14 feet.
Direct interchanges should be provided where "a large volume of interchanging traffic is expected." Otherwise, access would be "constructed in such manner as to permit exit from and entrance to the interregional highway by right-turning movements only." Preferably, ramps or connections would be provided in all four quadrants of the intersection, but at least two, one on each side of the highway, were to be provided. Ramps would connect with the service road rather than intersecting streets.
Bus stops were to be prohibited on urban sections, but access connections for bus stops were to be provided.
Pedestrians were to be prohibited on road surfaces and pavements. If shoulders are designed for pedestrians, the walk area "shall be separated from the edge of the pavement for vehicles by a curb and strip at least 6 feet wide." Overpasses would be designed to accommodate pedestrians.
If median strips or borders are wide enough "for pedestrian purposes or for recreational facilities, such as rest and comfort facilities and playgrounds for both road users and nearby residents," the facilities should be provided or space assigned for their future development.
Wherever feasible, the design "shall conserve desirable and irreplaceable landscape features, avoid needless damage to desirable trees and other growth and to lake and stream shores . . . ." Areas disturbed by construction "shall be appropriately recovered with suitable vegetative growth, and the additional landscaping shall be done where deemed necessary." Design and landscaping should be planned "to protect the highway against erosion by wind and water, to reduce maintenance to a minimum, and to enhance the natural appearance of the road and the wayside."
All traffic control signs would be prohibited.
Urban section would "be lighted by artificial fixed-source illumination to provide the maximum degree of safety and convenience of movement at night."